If there are lumps of butter remaining that will not blend, gently warm the butter on top of the hot oven or in the microwave for 10 seconds and blend again until smooth. (beyondthepeel.net)
Using your fingers and hands, work the butter into the flour mixture, until pea - sized lumps of butter are present. (hollyandflora.com)
I was glad to see the picture with the melted and cooled butter that has a little lump of butter left in it. (glutenfreeonashoestring.com)